This invention relates to catheter with a retractable cannula for delivering a plurality of chemicals.
In the past, catheters have been provided for delivering a chemical to a site within the body of the patient. Typically, such catheters have been provided with a single lumen for delivering the chemical. If it is desired to deliver a second chemical to the same site, or even to a second site, the lumen in the catheter for delivering the first chemical must be flushed clear of the first chemical before the second chemical can be delivered. This has been found to be undesirable in many situations, particularly because it is difficult to control the amount of chemical which is delivered to the patient site. In addition, an undue amount of time is required for delivering the two chemicals to the site. There is therefore a need for a new and improved catheter which can be used for delivering a plurality of chemicals.